1. Field of the Invention
The present invention relates to a spring manufacturing technique where a continuously fed wire which is to become, for example, a spring, is forcibly bent, wound, or coiled by tools in a spring forming space.
2. Description of the Related Art
A conventionally available spring manufacturing apparatus can form various shapes of springs by numerical control (e.g., U.S. Pat. No. 5,887,471). In this conventional spring manufacturing apparatus, a plurality of tools are arranged in a radial pattern on intervals of 45° on a forming table with a wire as its center, which is fed out to a spring forming space on the forming table, and each of the tools is supported by a tool supporting mechanism and independently driven by servomotors.
Since the conventional spring manufacturing apparatus does not comprise means for gripping the wire, which has been fed from the wire guide, formed into a partially(or partway) finished shape and cut, for processing the cut wire, it is impossible to re-perform processing on the cut and partially finished wire with the same apparatus and form the wire into a final shape. Therefore, in order to form, without cutting the wire, a spring having a complicated shape, for example, a double-torsion spring (torsion coil spring) whose wire ends are both coiled or wound, the plurality of tools shown in FIGS. 11 and 12 need to be moved in a precise and complicated fashion. This leaves room for improvement in productivity. Furthermore, if tools for exclusive use or a large number of tools are necessary, the number of servomotors for driving the tools also increases. While the apparatus' processing capability may be enhanced, there is still scope to improve the aspect of cost.